In exterior walls of building structures, such as houses or commercial buildings, there are a number of locations within the building structure where ambient moisture-laden air may become relatively trapped in still air. In time, the trapped moisture-laden air may condense in droplets or drops on adjacent surfaces of masonry, wood or metal which may not be visible to an observer or exposed for treatment. There has been substantial development of devices and arrangements for leading moisture away from relatively trapped areas in masonry and other types of building construction in an effort to overcome this problem.